The technology relates to a vehicle power source that may be mounted on a vehicle.
As a vehicle power source that may be mounted on a vehicle, a power source has been developed that allows electric power to be charged not only in a lead battery but also in a lithium ion battery; the electric power may be generated by an alternator in deceleration of a vehicle (refer to Japanese Unexamined Patent Application Publication (JP-A) No. 2014-36557). This makes it possible to regenerate much electric power in the deceleration of a vehicle, leading to enhancement in energy efficiency of the vehicle.
As described in JP-A No. 2014-36557, a vehicle power source may be provided with a switch that controls a coupling state of components such as, but not limited to, an alternator and a lithium ion battery. Such a switch of the vehicle power source may be switched to a conductive state or a cut-off state in accordance with a charge and discharge state. If a failure such as, but not limited to, a closed seizure and an opened seizure should occur in the switch, proper functioning of the vehicle power source may become difficult. It is therefore desired to determine presence or absence of a switch failure.